1. Extremely easy to debug and work with. Being able to debug effortlessly in PyCharm makes life very easy.
2. The API is quite clean and nice and fits in really well with Python and nothing feels hacky. I've developed my own Keras-like framework for experimentation, training and evaluating models quickly and easily and the entire experience has been really enjoyable.
3. The nicest thing though is that as the article points out, a huge percentage of researchers have moved to Pytorch and this allows us to more easily look at other researcher's code and experiment with things easily and incorporate ideas and cutting-edge research into our own work. Even for things that are released in TensorFlow, if it is an important publication that gains attention and traction in the community, you will likely have implementations in Pytorch pop up soon enough.
I do think that TensorFlow still has an edge on the deployment at scale/mobile side of things as pointed out by the article. But Pytorch is a lot younger and they are making a lot of progress with every release in that space.